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Catalyst regeneration techniques in naphtha reforming: Short review

Gupta Aviral, Gupta S. K.

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

101–-108

EN

Catalytic reforming is an important intermediate in the processing of crude (naphtha in particular) to obtain gasoline. The catalyst used in the process (platinum) is quite expensive and may negatively impact the business if not used judiciously. The aforesaid not only refers to the reduction in loss of the catalyst per unit of gasoline produced but also to the manufacturing of an environmentally friendlier product alongside which is the need of the planet and also a necessity to meet the increasingly strict government norms. In order to meet the above requirements, various refineries around the world use various well-known conventional methods which depend on the quality and quantity of crude manufactured by them. This paper focuses on highlighting recent advancements in methods of catalytic regeneration (CR) in the reforming unit of petroleum industries to produce high octane gasoline, without any major replacements in their existing setup. Research papers formulated by the application of methodologies involving non-linear models and real-time refinery data have only been considered to avoid any deviations/errors in practical applications. In-depth analysis of these papers has led to the origin of some ideas which have been included as suggestions and can be considered as subjects of further research. In all, the objective of the paper is to serve as a reference for researchers and engineers working on devising optimum methods to improve the regeneration of reforming catalysts.

2

Analysis of through transmission laser welding of Nylon6 by finite element simulation

Gupta S. K., Pal P. K.

Management and Production Engineering Review

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2018

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Vol. 9, No. 4

56--69

EN

Over the years laser welding has evolved as a fabrication process capable of overcoming the limitations of conventional joining methodologies. It facilitates the welding of diverse range of materials like metals, non-metals, polymers etc. Laser transmission welding is a technique employed for fabricating intricate shapes/contours in polymers with better precision compared to the other conventional processes. Nylon6, a synthetic semi-crystalline polymer is utilized as an engineering thermoplastic due to its high strength and temperature resistant properties. In the earlier researches, various welding techniques were employed for the fabrication of polymers and metals keeping the laser beam stagnant, and much emphasis was given only to temperature distribution along the different axes and limited attention was given to residual stress analysis. Therefore, in this research work, a three-dimensional time-dependent model using a moving laser beam is used to fabricate unreinforced Nylon6 specimens.

3

A Scheme for Template Security at Feature Fusion Level in Multimodal Biometric System

Selwal A., Gupta S. K., Kumar S.

Advances in Science and Technology. Research Journal

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2016

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Vol. 10, nr 31

23--30

EN

Biometrics is the science of human recognition by means of their biological, chemical or behavioural traits. These systems are used in many real life applications simply from biometric based attendance system to providing security at a very sophisticated level. A biometric system deals with raw data captured using a sensor and feature template extracted from raw image. One of the challenges being faced by designers of these systems is to secure template data extracted from the biometric modalities of the user and protect the raw images. In order to minimize spoof attacks on biometric systems by unauthorised users one of the solutions is to use multi-biometric systems. Multi-modal biometric system works by using fusion technique to merge feature templates generated from different modalities of the human. In this work, a novel scheme is proposed to secure template during feature fusion level. The scheme is based on union operation of fuzzy relations of templates of modalities during fusion process of multimodal biometric systems. This approach serves dual purpose of feature fusion as well as transformation of templates into a single secured non invertible template. The proposed technique is irreversible, diverse and experimentally tested on a bimodal biometric system comprising of fingerprint and hand geometry. The given scheme results into significant improvement in the performance of the system with lower equal error rate and improvement in genuine acceptance rate.

4

Anomalous Variations of Ionosphere Associated with the Strong Earthquake at Pakistan-Iran Border at a Low Latitude Station Agra, India

Pundhir D., Singh B., Singh O. P., Gupta S. K.

Acta Geophysica

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2016

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Vol. 64, no. 3

796--809

EN

In this paper, we analyze the TEC data for April 2013 observed at Agra station, India (geogr. lat. 27.2° N, long. 78° E) to examine the effect of earthquake of magnitude M = 7.8 which occurred on 16 April 2013 at Pakistan–Iran border region. We process the TEC data using the σ statistical criterion to find out anomalous variation in TEC data. We also study the VLF propagation signal from NPM, Hawaii (21.42° N, 158° W), which is monitored at the same station (Agra station) in the light of this earthquake as well as solar flares. The nighttime fluctuation method is used to analyze the VLF data for the period of ±5 days from the day of earthquake (11-21 April 2013). The anomalous enhancements and depletions are found in TEC data on 1-9 days before the occurrence of event.

5

Thermally assisted OSL: a potent tool for improvement in minimum detectable dose and extension of dose range of Al2O3:C

Soni A., Mishra D. R., Bhatt B. C., Gupta S. K., Rawat N. S., Kulkarni M. S., Sharma D. N.

Geochronometria

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2013

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Vol. 40, no. 4

258--265

EN

The influence of electron-phonon interaction on the shape of the optically stimulated lumi-nescence decay curve of Al2O3:C has been studied using thermally assisted optically stimulated lumi-nescence (TA-OSL). The minimum detectable dose (MDD) of a phosphor depends on the standard deviation of the background signal which affects the signal-to-noise ratio. The standard deviation of the background signal reduces at lower stimulation light intensity while the readout time increases. Further, measurement at higher temperature enhances the OSL signal with faster decay due to the temperature dependence of photo-ionization cross-section. To achieve the same decay constant and more signal, the temperature of measurement was raised. As a result of lowering the stimulation in-tensity at higher temperature (85°C) the overall MDD of α-Al2O3:C was found to improve by 1.8 times. For extension of dose linearity in higher range, deeper traps were studied by simultaneous ap-plication of CW-OSL and thermal stimulation up to 400°C, using a linear heating rate of 4K/s. By us-ing this method, two well defined peaks at 121°C and 232°C were observed. These TA-OSL peaks have been correlated with two deeper defects which can be thermally bleached at 650°C and 900°C respectively. These deeper defects are stable up to 500°C, so they can store absorbed dose infor-mation even if the sample is inadvertently exposed to light or heat. The dose vs. TA-OSL response from deep traps of α-Al2O3:C was found to be linear up to 10 kGy, thus extending its application for high dose dosimetry.

6

On the wave propagation in generalised thermoelastic media

Sharma J. N., Sharma P. K., Gupta S. K.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no 2

299-316

EN

In this paper, the analysis is based on the decoupled field equations of linear thermoelasticity without energy dissipation. These equations have been solved with the use of integral transforms. The dynamic behavior of an elastic half space due to (i) a line load and (ii) a mechanical load, acting on the boundary is also discussed. While the displacement in both of the cases is found to be continuous, the temperature, strain and stress are observed to be discontinuous at elastic and thermal wave fronts. The characteristic features of the underlying theory are analyzed in the light of these solutions and their counterparts in earlier works. The results obtained theoretically have been computed numerically and are represented graphically.